The recent popularity of a new antenna cable called Skyhighgain Coax has
created a safety problem for users and a nightmare for firefighters.
SHGC was developed theoretically by Tricenters Experimental Laboratories,
Inc. as a signal-boosting element for use in radio and television
transmission lines. Scientists at TELI discovered that when a bias
voltage is applied to the special material used to make SHGC the effect
was incredible. Instead of simply reducing signal loss, the signal
strength increased!

Amplification of RF (radio-frequency) signals in the new coaxial
transmission cable was actually greater than 3 db (decibels) per meter
per meter. (Read that again.)

In laymen's terms, that means that for every 10 centimeters a signal
travels through the cable the signal strength doubles! Put 1 Watt of
RF energy into one end of a one meter length of SHGC and you get 2
Watts at the other end (assuming you supply the bias voltage, of course).
At two meters you get 4 Watts. At three meters the signal strength
increases to eight Watts. Doubling the power every meter the total
effective power of the signal exceeds 1,000 Watts by the time it has
traveled only 10 meters up the line.

Now imagine what would happen if you had a 100-meter SHGC cable.
(The actual figures are shown at the end of this article.)

In conventional transmission lines there is always some loss of signal
depending upon frequency and the electric characterists of the cable.
But with SHGC, instead of a loss, you get a gain in signal strength.
This is the stuff every radio engineer has dreamed of.

But here's the problem. The unwary (and mathematically challanged)
average user seems to think that if a short section of SHGC inserted
in his transmission line is good, then a longer one is better. If one
were to, say substitute SHGC for the complete run from their radio
shack to the top of their tower, the signal would have more energy
than the cable (or the antenna) could withstand. (The 20-meter traps
on the tri-band beam that used to be on the 60-meter Rohn 25g tower
behind the house in the photograph above were never found.)

Designed to be used in short sections between standard coax and the
antenna, SHGC is not currently available, pending the resolution of
certain limiting manufacturing capabilities. Some reports have surfaced
however that a few samples of the hot-pink colored coax have somehow
slipped past reality checkpoints and made their way into the Amateur
(and amateur) community. And without official spec sheets and
installation guides SHGC poses a significant hazard to the uneducated.

The following table dramatically illustrates the danger of using too
much Skyhighgain Coax in any transmission line.

Length of Coax / Power Output

1 meters - 2 Watts

2 meters - 4 Watts

3 meters - 8 Watts

4 meters - 16 Watts

5 meters - 32 Watts

6 meters - 64 Watts

7 meters - 128 Watts

8 meters - 256 Watts

9 meters - 512 Watts

10 meters - 1,024 Watts

11 meters - 2,048 Watts

12 meters - 4,096 Watts

13 meters - 8,192 Watts

14 meters - 16,384 Watts

15 meters - 32,768 Watts

16 meters - 65,536 Watts

17 meters - 131,072 Watts

18 meters - 262,144 Watts

19 meters - 524,288 Watts

20 meters - 1,048,576 Watts

21 meters - 2,097,152 Watts

22 meters - 4,194,304 Watts

23 meters - 8,388,608 Watts

24 meters - 16,777,216 Watts

25 meters - 33,554,432 Watts

As you can see, by the time you reach only 20 meters, the signal power
has exceeded a million Watts! Assumming your facility's commercial
power mains could handle the load, the signal would exceed 30 million
Watts at only 25 meters from the transmitter.

Of course, most power main breakers would trip long before the million
Watt level, but once the signal starts up the transmisison line the
peak envelope power (PEP) climbs so fast that there is a possibility
that the circuit breakers would either fuse or the electric current
would simply jump the breaker's open switch gap and power would
continue to increase until the primary main lines evaporated in what
could only be described as an artificial bolt of lightning, showering
every surrounding structure in hot plasma and sparks.